The present invention relates to a process for manufacturing an α-dihydroxy derivative from an aryl allyl ether and converting such α-dihydroxy derivative to an epoxy resin. The α-dihydroxy derivative may optionally be used to produce an α-halohydrin intermediate which, in turn, is used to make an epoxy resin. For example, the process of the present invention is useful for manufacturing a bisphenol A (bis A) epoxy resin.
In a well-known industrial process for producing epoxy resins on a large commercial scale, in a first step, an α-halohydrin, as a reactive intermediate, is made by reacting an active hydrogen-containing compound such as an alcohol, a phenol, a carboxylic acid or an amine with an epoxide-containing epihalohydrin, such as epichlorohydrin (ECH) or epibromohydrin. In this first step, the epoxide moiety of the epihalohydrin is consumed in the formation of the α-halohydrin moiety. Then, in a second step, the α-halohydrin moiety is converted back into an epoxide moiety of a glycidyl ether, glycidyl ester, or glycidyl amine under basic reaction conditions.
The most widely made and particularly useful epoxy resin is bis A epoxy resin which is made by the coupling reaction of bis A and ECH through the epoxy moiety of ECH to form the bis(α-chlorohydrin) intermediate in a first step. Then, in a dehydrochlorination reaction with base in which an epoxide moiety is reformed, as a second step, the bis A bis(α-chlorohydrin) intermediate is converted to the bis A diglycidyl ether epoxy resin. Such a two-step process for making an epoxy resin is described by H. Lee and K. Neville in “Handbook of Epoxy Resins”, McGraw-Hill Book Co., New York, N.Y., 1982, Reissue, 2-3 to 2-4. This process is shown in the following reaction sequence, Reaction Sequence (I). More specifically, Reaction Sequence (I) shows a process chemistry scheme for a two-step, industrial manufacture of bis A epoxy resin via the reaction of bis A and ECH to make a chlorohydrin intermediate. 
The above two-step process of coupling bis A and ECH by reaction at the epoxide ring followed by epoxide ring-forming dehydrochlorination has also been combined into a single-step reaction, wherein the bis(α-chlorohydrin) intermediate of bis A is generated in situ and converted into an epoxy simultaneously. Such a single-step process for making bis A epoxy resin is described in U.S. Pat. Nos. 4,499,255; 4,778,863; and 5,028,686.
Another method to generate α-chlorohydrins, as reactive intermeditates, that does not consume an epoxide moeity of any of the reactants, is described in U.S. Pat. No. 2,144,612 in which glycerol, which is an α-dihydroxy derivative, is converted into an α-chlorohydrin by reaction with anhydrous hydrogen chloride (HCl) in the presence of a catalytic amount of acetic acid (AcOH). U.S. Pat. No. 2,144,612 describes a process that is shown in the following reaction sequence, Reaction Sequence (II), for making glycerol dichlorohydrin, a precursor for epichlorohydrin from the α-dihydroxy derivative glycerol. More specifically, Reaction Sequence (II) shows chemistry for epichlorohydrin synthesis via the reaction of glycerol with hydrogen chloride and acetic acid to make glycerol dichlorohydrin. 
Although ECH is an important commercial product for making α-chlorohydrin intermediates, and particularly for making the bis A bis(α-chlorohydrin) intermediate precursors of bis A epoxy resin, ECH provides a chlorine-intensive route to producing epoxy resins. In the predominate commercial process for making ECH, ECH is made from allyl chloride, which in turn, is made from thermal chlorination of propylene using chlorine gas, a process that produces chlorinated by-products. Generally, chlorinated by-products are treated as waste material.
Additionally, a large amount of water is used when converting allyl chloride into an α-chlorohydrin intermediate and then converting the α-chlorohydrin to ECH, and this water must eventually also be treated as waste. Therefore, from an environmental standpoint, there is a desire to reduce the consumption of chlorine and to reduce the generation of chlorinated by-products and waste water in the production of epoxy resin.
In addition, epoxy resins made from ECH by either of the previously described two-step or single-step processes, may have a high organic chloride content which may be deemed as undesirable in some applications, for example, in electronic applications.
It is therefore desired to provide a non-epichlorohydrin process for making epoxy resins such as bis A epoxy resin. That is, it is desired to provide an alternative epoxy resin route, i.e., an alternative process without using ECH for manufacturing epoxy resins.
One non-epichlorohydrin process for manufacturing epoxy resins is described in U.S. Pat. No. 6,001,945. In the process of U.S. Pat. No. 6,001,945, the epoxide moeity of the reactant glycidol is coupled with bis A to produce an α-dihydroxy derivative, which is subsequently converted to an α-chldrohydrin via reaction with hydrogen chloride and a catalytic amount of acetic acid via the process described in U.S. Pat. No. 2,144,612. Glycidol is known to be a highly toxic and thermally unstable material tending to explosively self-polymerize. At low temperatures, such as 70° C., glycidol is unstable and the loss of epoxide content of glycidol is significant. Glycidol self-polymerization diminishes glycidol selectivity and product yield in its reactions, and the glycidol self-polymerization products complicate separation and purification of the desired reaction product. These undesirable properties of glycidol are described in detail by A. Kleemann and R. Wagner in “Glycidol Properties, Reactions, Applications”, Dr. Alfred Huthig Verlag, New York, N.Y., 1981, pp. 48-52. Thus, it is also desirable to develop processes that can manufacture α-halohydrin intermediates as precursors for manufacturing epoxy resins that do not require glycidol as a reactant.
U.S. Patent Application Ser. No. 60/205,366 entitled “Process for Manufacturing a Halohydrin Intermediate and Epoxy Resins Prepared Therefrom,” filed by Boriack et al., May 18, 2000, discloses a process for manufacturing an α-halohydrin intermediate of at least one or more phenols and utilizing such α-halohydrin intermediate of the least one or more phenols to make an epoxy resin such as bis A epoxy resin. The above patent application is an improvement over U.S. Pat. No. 6,001,945 by utilizing a stable glycidyl acetate in the place of a highly unstable glycidol. However, even both processes above, consume the epoxide group of an epoxide-containing raw material to make an intermediate which must be subsequently re-epoxidized.
It is therefore desired to provide a novel, alternative process for manufacturing epoxy resins without the use of glycidol or epichlorohydrin.